<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{width: 280px;height: 352px;margin: 20px auto;display: grid;
            grid-template-rows: repeat(4,1fr);
            grid-template-columns: repeat(3,1fr);
            grid-template-areas: 
            "a1 a2 a2"
            "a3 a2 a2"
            "a4 a4 a5"
            "a6 a7 a7";
            gap: 6px 6px;
        }
        .box div{background: red;}
        .box div:nth-child(1){grid-area: a1;}
        .box div:nth-child(2){grid-area: a2;}
        .box div:nth-child(3){grid-area: a3;}
        .box div:nth-child(4){grid-area: a4;}
        .box div:nth-child(5){grid-area: a5;}
        .box div:nth-child(6){grid-area: a6;}
        .box div:nth-child(7){grid-area: a7;}
    </style>
</head>
<body>
    <div class="box">
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
        <div></div>
    </div>
</body>
</html>